Track membrane with immobilized colloid silver particles

A method for modification of track membranes by immobilization of polymer complexes of colloid silver nanoparticles on the surface of microfiltration membranes was developed. The antimicrobial properties of track membranes modified with silver nanoparticles were tested on E. coli, Ps. aeruginosa, St. aureus, and B. cereus.     

The rotational mobility of fulleropyrrolineoxyl in toluene solution

The rotational mobility of a stable fullerene-based nitroxyl radical (fulleropyrrolineoxyl) in toluene was studied. The rotational correlation time of fulleropyrrolineoxyl was found to be about eight times longer than that of 4-oxy-2,2,6,6-tetramethylpiperidine-1-oxyl. The activation energy of the rotational motion of both probes was determined and their hydrodynamic radii estimated.     

High-performance liquid radiochromatography: Its application for stability study of [3H] stobadin

An HPLC method was developed for studying the stability of [³H] stobadin stored in physiological saline or buffers at various pH. Optimum conditions for the separation of degradation products were elaborated. A high-performance liquid chromatograph equipped with a radioactivity detector was used.     

Thermodynamic parameters of intermolecular interaction in strongly associated solvents and their mixtures with dimethylformamide

The specific and nonspecific constituents of the total energy of intermolecular interasction in ethylene glycol, diethylene glycol, and formamide were determined for the range 288.15–323.15 K using a simulation approach. Diethylene glycol, like formamide and ethylene glycol, forms networks of hydrogen bonds. In ethylene glycol and formamide, the hydrogen bonds make a predominant contribution to the total interaction energy. The specific and nonspecific contributions in mixtures of the above solvents with dimethyl-formamide were calculated, and the results were discussed in combination with the data for aqueous dimethyl-formamide solutions.Translated from Zhurnal Obshchei Khimii, Vol. 74, No. 11, 2004, pp. 1789–1796.Original Russian Text Copyright © 2004 by Zaichikov, KrestyaninovThis revised version was published online in April 2005 with a corrected cover date.     

Thermochemical aspects of interaction of polyimide composites with organic sorbents

Interaction of ITA-31 polyimide binder with a series of industrial sorbents based on styrene and vinylpyridine derivatives was studied.     

Use of potassium permanganate as a possible kinetic standard in thermal analysis

Analysis of the mechanism of congruent dissociative evaporation of solid substances led to a suggestion that potassium permanganate can be used as a possible kinetic standard in thermal analysis.     

Formation of thin carbon films containing metal nanoparticles by thermolysis of a polymer precursor

A new procedure was developed for preparing carbon films with magnetic metal nanoparticles by thermolysis of a polymer precursor. The conditions for preparing carbon films with required surface concentration of the metal nanoparticles and hence with dielectric or metallic properties were determined.     

Defect magnesium oxides containing acetate and nitrate ion fragments incorporated in the oxide structure

The results of studies on the synthesis of defect magnesium oxides by MgO hydration in salt solutions are summarized. The incorporation of oxygen-containing salt anions into the anionic hydroxide/oxide framework is described. In this case, the anion residue whose oxygen atoms belong to the oxygen framework of the oxide is incorporated in the octahedral oxygen cell of the oxide to occupy the place of a virtual magnesium cation. A portion of cationic vacancies remains free, whereas a portion is occupied by the transformed anion residue with a positive charge other than 2+. As a result, defect magnesium oxides are formed as substitutional solid solutions. The structure and charge heterogeneity of defect oxides is responsible for their high catalytic activity.     

Hydrogen peroxide formation in the oxidation of carbonyl-containing compounds at β-CH bonds

The concepts of the selective inhibition of reactions with the participation of HO ₂^· radicals by nitrobenzene in accordance with a cyclic mechanism were supported using cyclohexanol oxidation as an example. It was demonstrated that the nitroxyl radical generated from nitrobenzene selectively reacts with HO₂ ^· to form hydrogen peroxide and nitrobenzene. A decrease in the rates of oxidation of esters, carboxylic acids, and ketones with specially chosen structures in the presence of nitrobenzene, as well as the detection of H₂O₂ and corresponding ,-unsaturated compounds among the reaction products, indicated that the degradation of -peroxyl radicals of the above compounds occurred under conditions of the liquid-phase oxidation of organic substances that result in the formation of the HO₂^· radical and an unsaturated compound.Translated from Kinetika i Kataliz, Vol. 45, No. 6, 2004, pp. 814–820.Original Russian Text Copyright © 2004 by Nepomnyashchikh, Nosacheva, Perkel.     

Calorimetric determination of solubility of water in pectin and physical state diagram of a pectin-water system

For the mixtures of pectin of different esterification degrees and water, heat capacities in the range of 80–320 K have been measured, and DTA measurements have been carried out in the range 80–450 K. The effect of water on the physical transitions of pectin has been studied, and the solubility of water in pectins of different esterification degrees at the temperature of melting of a liquid component has been determined. On the basis on the experimental data, the physical state diagram of the pectin-water system has been constructed and analyzed for the whole range of component concentrations within a wide temperature interval.